Rotary engine for rock drills



Feb. 15,1927.

. A. H. KATTERJOHN ROTARY ENGINE FOR ROCK DRILLS Filed Feb. 28, 1923 Patented Feb. 15, 1927.

UNITED STATES.

PATENT OFFICE.

AUGUST H. KATTERJOI-IN, OF DENVER, COLORADO, ASSIGNOR TO THE DENVER ROCK DRILL MANUFACTURING- GOMPANY, OIE DENVER, COLORADO, A CORPORATION OF DELAWARE.

ROTARY ENGINE FOR ROCK DRILLS.

Application filed February 28, 1923.

The present invention while particularly intended for use in :connection with the chuck rotating motor of a rock drill, may possibly be employed in other relations. The object in view is to provide means whereby the exhaust is muilled'without creating undue back pressure.

An embodiment which has been found very satisfactory is illustrated in the accompanying drawings, wherein Figure 1 is a side elevation of a portion of a rock drill showing the chuck rotating motor in elevation and illustrating the muiiler.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

As is well known in rock drills, a rotary motor may be employed for effecting the rotation of the steel-holding chuck, and a satistactory type of motor is that in which intermeshing gear pistons are employed. In the embodiment disclosed a portion of a barrel or body of a rock drill is indicated at 3, and forming a part thereof, is a cylinder member 1 containing a chamber 5, in which are located the intermeshing gear pistons 6. Motive fluid is supplied to the piston chamber 5 by a conduit indicated at 7, said conduit leading, in the present instance, to the lower side of the piston chamber and below the intermcshing portions of the gear pis ton 6.

One head of the piston chamber 5 is integral with the body 3. the opposite side of said piston opening through the body and being closed by a removable cap plate or head. 8. Said head is provided with a diagonally disposed enlargement 9 in which is formed an exhaust chamber 10 of considerable capacity that is closed at its upper end and has its lower end open. Into said upper end opens an exhaust port 11 that communicates with the upper portion of the piston chamber 5 above the intermeshing portions of the gear pistons, this port being disposed transversely to the chamber 10. Threaded into the lower end of the chamber 10 is a nipple 12 having an exhaust port 13 longitudinally therethrough that is in communica- Serial No. 621,861.

tion with the chamber 10 and being disposed longitudinally thereof is at substantially right angles to the port 11. The ports 11 and 13 are of less diameter than the cross sectional area of the chamber 10.

As a result of this arrangement, the ex pansible motive fluid after operating on the 4' pistons escapes through the port 11 into the relatively large chamber 10 so that it expands to some extent therein and finally escapes through the port 13 to atmosphere. As a consequence a double expansion takes place which breaks up the pulsations in the exhaust and makes the operation of the motor very much more quiet than when the exhaust takes place directly to atmosphere. In this connection it must be borne in mind that in the operation of the turbine or rotary engine each tooth on the two gears acts successively as a piston. As these teeth in rapid succession uncover to the exhaust port a shrill siren effect is produced that is very disagreeable, and it is this sound that is substantially nullified or greatly minimized.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art, without further description, and it will be understood that various changes in the size, shape, proportion and minor details of construction, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a rotary motor, a cylinder member having heads, one of said heads having an enlargement on its outer side, said enlarge ment having a longitudinal bore extending in from one end and terminating short of the other end,'said head having an exhaust port opening into the inner end of the bore adjacent its closed end, and a plug fitted into the open end and having an exhaust opening therethrough less in diameter'than the bore. 95

2. In a rotary motor, a cylinder member Lil the other end, said head having an exhaust port opening into the inner end of the bore adjacent its closed end, and a plug fitted into the open end and having an exhaust 10 opening therethrough less in diameter than the bore.

In testimony whereof, I aflix my signature.

AUGUST I-I. KATTERJOHN. 

